property_cache_util.h

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/*
 * Copyright 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef NET_INSTAWEB_REWRITER_PUBLIC_PROPERTY_CACHE_UTIL_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_PROPERTY_CACHE_UTIL_H_

#include "net/instaweb/rewriter/public/rewrite_driver.h"
#include "net/instaweb/rewriter/public/server_context.h"
#include "net/instaweb/util/public/property_cache.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/proto_util.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

enum PropertyCacheDecodeResult {
  kPropertyCacheDecodeNotFound,  
  kPropertyCacheDecodeExpired,
  kPropertyCacheDecodeParseError,
  kPropertyCacheDecodeOk
};

const PropertyValue* DecodeFromPropertyCacheHelper(
    const PropertyCache* cache,
    AbstractPropertyPage* page,
    const PropertyCache::Cohort* cohort,
    StringPiece property_name,
    int64 cache_ttl_ms,
    PropertyCacheDecodeResult* status);

template<typename T>
T* DecodeFromPropertyCache(const PropertyCache* cache,
                           AbstractPropertyPage* page,
                           const PropertyCache::Cohort* cohort,
                           StringPiece property_name,
                           int64 cache_ttl_ms,
                           PropertyCacheDecodeResult* status) {
  const PropertyValue* property_value =
      DecodeFromPropertyCacheHelper(cache, page, cohort, property_name,
                                    cache_ttl_ms, status);
  if (property_value == NULL) {
    return NULL;
  }

  scoped_ptr<T> result(new T);
  ArrayInputStream input(property_value->value().data(),
                         property_value->value().size());
  if (!result->ParseFromZeroCopyStream(&input)) {
    *status = kPropertyCacheDecodeParseError;
    return NULL;
  }

  *status = kPropertyCacheDecodeOk;
  return result.release();
}

template<typename T>
T* DecodeFromPropertyCache(RewriteDriver* driver,
                           const PropertyCache::Cohort* cohort,
                           StringPiece property_name,
                           int64 cache_ttl_ms,
                           PropertyCacheDecodeResult* status) {
  return DecodeFromPropertyCache<T>(
      driver->server_context()->page_property_cache(),
      driver->property_page(),
      cohort,
      property_name,
      cache_ttl_ms,
      status);
}

enum PropertyCacheUpdateResult {
  kPropertyCacheUpdateNotFound,  
  kPropertyCacheUpdateEncodeError,
  kPropertyCacheUpdateOk
};

PropertyCacheUpdateResult UpdateInPropertyCache(
    const protobuf::MessageLite& value,
    const PropertyCache::Cohort* cohort,
    StringPiece property_name,
    bool write_cohort,
    AbstractPropertyPage* page);

inline PropertyCacheUpdateResult UpdateInPropertyCache(
    const protobuf::MessageLite& value, RewriteDriver* driver,
    const PropertyCache::Cohort* cohort, StringPiece property_name,
    bool write_cohort) {
  AbstractPropertyPage* page = driver->property_page();
  return UpdateInPropertyCache(
      value, cohort, property_name, write_cohort, page);
}

}  

#endif